Intro to Hormone Physiology Flashcards

1
Q

When the thyroid gland produces a hormone called T4, what happens?

A

Also known as Thyroxine, once produced, will travel to the liver via the bloodstream to be converted to its active form, T3, Triiodothyronine to stimulate energy production so that the liver can perform detoxification and other metabolic functions.

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2
Q

What is the hypothalamus?

A

A very small, cone-shaped gland within the brain.
Its job is to read and interpret hormone levels within the blood and nervous system.

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2
Q

How does the hypothalamus work?

A

In response to the messages it receives from the blood & nervous system, it produces and secretes certain neurohormones and then delivers those messages directly to the pituitary gland.

You can think of the hypothalamus as the big boss CEO to the entire endocrine system.

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2
Q

What is the hypothalamus’s primary role?

A

To maintain homeostasis.

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2
Q

How does the hypothalamus maintain homeostasis?

A

By secreting certain hormonal messages at a faster or slower pace depending upon what external cue it’s receiving (either releasing or inhibiting hormone to help start or stop hormone production further down the line)

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2
Q

What is GHRH/GHIH?

A

Growth Hormone-Releasing Hormone / Growth Hormone Inhibiting Hormone

Stimulates the release of growth hormone or inhibits it

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2
Q

What is TRH?

A

Thyrotropin-Releasing Hormone

Stimulates the pituitary to communicate with the thyroid

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2
Q

What is PRH/PIH?

A

Prolactin-Releasing Hormone/Prolactin Inhibiting Hormone

Stimulates the release of prolactin or inhibits it

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2
Q

What is CRH?

A

Corticotropin-Releasing Hormone

Stimulates the pituitary to communicate to the adrenals

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2
Q

What is GnRH?

A

Gonadotropin-Releasing Hormone

Stimulates the pituitary to communicate with the gonads

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3
Q

What role does the pituitary play?

A

It’s like the middleman or the primary supervisor. Although the hypothalamus is in contro, it can’t do much without the pituitary’s help.

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3
Q

What is the pituitary gland?

A

It is located just below the hypothalamus within the brain and is divided into two distinct lobes: the anterior pituitary and the posterior pituitary.

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3
Q

If there’s a disconnection between the communication of the hypothalamus and pituitary what can happen?

A

It can lead to hormones lost in translation and various imbalances and complications.

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3
Q

What hormones does the pituitary produce?

A
  • GH: Growth Hormone in response to GHRH or GHIH
  • PRL: Prolactin in responses to PRL or PIH
  • TSH: In response to TRH
  • ACTH: Adrenocorticotropic hormone in response to CRH
  • LH: Luteinizing Hormone
  • FSH: Follicle stimulating hormone in response to GnRH
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3
Q

What is the posterior pituitary?

A

Considered the neuronal lobe as it stores certain hormones produced in the hypothalamus and secretes them upon demand.

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3
Q

What is the anterior pituitary?

A

Considered to be a glandular lobe because it produces and secretes hormones directly

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3
Q

Do the hromones that are delivered from the hypothalamus to the pituitary reach the full circulatory system?

A

No they never reach it, they are directly connected between the hypophyseal portal system.

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4
Q

What are the Anterior pituitary hormones and their target tissues?

A
  • ACTH - delivered to the adrenal glands
  • TSH - delivered to the thyroid
  • GH - delivered to the bone, muscles, and other various tissues
  • PRL - delivered to the breast tissue after childbirth
  • LH & FSH - delivered to the ovaries to facilitate ovulation
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5
Q

What are the posterior pituitary hormones and their target tissues?

A
  • ADH - anti-diuretic hormone which is delivered to the kidney, to tell it how much water to conserve
  • OXT: Oxytocin
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6
Q

What is the pineal gland?

A

It resembles a small pine cone. Its main job is to control the body’s circadian rhyth, which is the wake and sleep cycle.

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7
Q

How is melatonin produced?

A

In response to light exposure to the retinas.

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8
Q

When is melatonin suppressed?

A

In exposure to light, specifically the blue light spectrum from sunlight, LED and fluorescnet lightings.

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9
Q

What is the Cortisol Awakening Response?

A

The blue light is emitted from the sun first thing in the morning which stimulates our bodies to wake us up.

When the sun goes down, cortisol is decreased, and melatonin takes over, completing the circadian rhythm.

When one hormone is up, the other is down.

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10
Q

Is melatonin a powerful free radical scavenger and anti-inflammatory hormone?

A

Yes. at night melatonin is working hard to promote inflammation balance and reduce tissue damage from oxidative stress.

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11
Q

Where is melatonin produced?

A

Within the Pinealocytes, the primary cells located in the pineal gland from the conversino of the neurotransmitter Serotonin.

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12
Q

How is Serotonin produced?

A

From the essential amino acid, Trypotophan, commonly found in animal-based proteins and complex carbohydrates.

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13
Q

How much of serotonin production occurs within the gut?

A

95%, as serotonin acts as an important regulator of the migrating motor complex.

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14
Q

The production of melatonin is heavily influenced by what?

A

Trypotophan, Serotonin, and B vitamins

Digestive issues and nutrient deficinecies in these areas may decrease one’s ability to properly produce melatonin which can lead to cortisol dominance, impacting sleep quality and perpetuating oxidative damange.

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15
Q

What is the Thyroid Gland?

A

A butterfly-shaped gland located along the windpipe.

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16
Q

What is the thyroid’s primary job?

A

To regulate metabolism, which is the process of producing energy within cells from the food that we consume

Facilitating growth and development, aiding in protein synthesis and maintaining mineral balance, specifically with the minerals Calcium and Iodine.

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17
Q

Where is thyroid hormone produced?

A

Between the follicular epithelial cells and the colloid (also known as the lumen) of the thyroid gland

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18
Q

How long is thyroid hormone stored?

A

Roughly 3 months until stimulated by Thyroid-Stimulating Hormone or TSH from the pituitary.

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19
Q

What plays a major role in calcium regulation with the parathyroid?

A

Calcitonin is produced in the parafollicular cells aka the “C cells” within the thyroid

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20
Q

What is thyroid hormone produced from?

A

A combination of the amino acid tyrosine and the mineral iodine.

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21
Q

How much does the thyroid produce?

A

About 90% inactive T4 (Thyroxine) and 10% active T3 (Triiodothyronine).

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22
Q

What does the T in the thyroid hormone demonstrate?

A

How many iodine atoms are present.

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23
Q

How many iodine atoms are present in the inactive version of thyroid hormone?

A

4

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24
Q

In order to activate the thyroid hormone to T3, what needs to happen?

A

An iodine atom must be removed.
80% of this process occurs within the liver, kidneys, and brain, as well as within every cell of the body.

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25
Q

When is T3 commonly elevated?

A

In the presence of inflammation and may be a common reason behind subclinical hypothyroid symptoms.

26
Q

What happens when T4 and T3 are converted into Reverse T3?

A

It has the opposite effect by slowing down metabolic function

27
Q

How much of thyroid hormone is bound to proteins within the bloodstream?

A

Roughly 99%; these binding proteins help to facilitate transport of the thyroid hormones to their target tissues

28
Q

What percentages of thryoid hormone is bound?

A

70 - 80% is bound to Thyroid Binding Globulin (TBG)
10-15% is bound to Albumin
10-15% is bound to Transthyretin (TTR)

29
Q

What percentage of thyroid hormone is free & unbound?

A

Only 1%

30
Q

What thyroid hormone is small enough to bypass the capillaries and be utilized by the tissues?

A

Free thyroid hormone (known as Free T4 and Free T3)

31
Q

Why do we want to always observe the concentration of free hormones when assessing thyroid health through measures?

A

Total T4 and Total T3 are representations of thyroid hormone that is both bound and free, observing the concentration of free hormones when assessing thyroid health through blood measures provides us with an understanding of what amount of thyroid hormone is actually usable by target tissues

32
Q

What is the Parathyroid (PTH)?

A

It consists of 4 small glands that rest right behind the thyroid. Each of these glands is about the size of a grain of rice.

33
Q

How does the parathyroid work?

A

Within a feedback loop, helping to regulate calcium & phosphorus levels within the blood, playing a major role in regulating pH.

34
Q

What is Addison’s disease?

A

an autoimmune condition where the adrenal glands can’t produce enough cortisol and aldosterone.

35
Q

Why is PTH produced?

Parathyroid hormone

A

When the parathyroid senses that blood calcium levels have dropped, they produce PTH in response.

36
Q

What does PTH do and how?

A
  • Causes direct reabsorption of calcium from urine
  • In bone, it causes resorption of bone, releasing calcium from the bone back into the bloodstream
  • In the gut, it stimualtes the production of Calcitriol
37
Q

What is Calcitonin’s job?

A

To directly oppose parathyroid hormone, stopping the production and secretion.

38
Q

What is Calcitrol?

A

the bioactive form of Vitamin D that helps to up-regulate the absorption of calcium via the intestines.

39
Q

Do serum calcium levels often move in parallel with serum Vitamin D levels?

A

Yes because the bioactive form of Vitamin D that helps upregulate the absorption of calcium via the intestines.

40
Q

Why is calcium so important?

A

It plays a major role in muscle contraction, and the conduction of electrical currents along our nerves, which is important for muscle contraction, such as contractions of the uterus during menstruation and childbirth.

Also for fetal bone development in pregnancy and during lactation

41
Q

What is the Thymus Gland?

A

A gland that sits behind the sternum and produces a hormone called Thymostin

42
Q

What does Thymostin do?

A

Stimulates the development of major immune cells in the body such as T-Lymphocyte cells, otherwise known as T cells

43
Q

Does your body produce all of your T cells by the time you reach puberty?

A

Yes, it is thought that that is the case

44
Q

What is the Pancreas?

A

It is a gland that acts as both an endocrine and exocrine gland.

45
Q

What is the main difference between an endocrine an exocrine gland?

A

Exocrine glands secrete substances other than hormones into local tissues via ducts whereas endocrine glands secrete hormones through the vascular system, without ducts.

46
Q
A
47
Q

What are some examples of exocrine glands?

A
  • Sweat glands
  • Salivary glands
  • Bartholin glands, which help produce vaginal lubrication
48
Q

What does the pancreas do?

A

It acts as an endocrine gland by secreting the hormones Insulin & Glucagon into the bloodstream to regulate blood sugar levels

It acts as an exxocrine gland by secreting bicarbonate and enzymes into the small intestine via ducts to help facilitate digestion

49
Q

What are the Islets of Langerhans?

A

A group of cells within the pancreas that are directly connected to the vascular network.

They contain beta cells that produce insulin

They contain alpha cells which produce gluagon

They contain delta cells which produce a hormone called somatostatin

50
Q

What does insulin do?

A

It’s a hormone whose function is to help remove glucose from the bloodstream by delivering it to cells for energy production or fat storage

51
Q

What does glucagon do?

A

It helps to elevate blood gluclose in times of low blood sugar

52
Q

What does somatostatin do?

A

It plays a role in inhibiting somatotropin (otherwise known as growth hormone), insulin, and glucagon.

It is also produced by the hypothalamus to inhibit the secretion of growth hormone by the pituitary gland.

53
Q

What are the Acinar cells?

A

They are in the pancreas and are connected to the pancreatic duct systems and produce the bicarbonate and enzymes needed to facilitate digestion.

The acinar cells are stimulated by the parasympathetic nervous sytem and inhibited by the sympathetic nervous system, which is one reason why digestive function works best in a relaxed and calm state of mind.

54
Q

What are the Adrenal Glands?

A

Two triangle shaped glands that are nestled right above each kidney.

55
Q

What do the adrenals do?

A

They play a major role in regulating the body’s stress response, metabolism, and blood sugar balance.

They produce a portion of our steroid sex hormones and work directly with the kidneys to help balance electrolytes, and maintain proper blood pressure levels .

56
Q

What is each adrenal gland comprised of?

A

two distinct layers, the adrenal cortex, and the adrenal medulla

57
Q

What are the 3 sub-layers that the adrenal cortex can be broken into?

A
  • Zona Glomerulosa
  • Zona Fasciculata
  • Zona Reticularis

Each produce specific types of corticosteroid hormones

58
Q

What are corticosteroid hormones?

A

Fat-soluble hormones produced within the adrenal cortex

59
Q

What does the Zona Glomerulosa produce?

A

Mineralocortcoids such as aldosterone

60
Q

What does the Zona Fasciculata produce?

A

The glucocorticoid Cortisol

61
Q

What does the Zona Reticularis produce?

A

Steroid sex hormones known as Androgens

62
Q

What is Aldosterone?

A

A hormone that helps to regulate sodium and potassium balance with the kidneys, helping to maintain healthy blood preassure and systemic pH.

63
Q

What is cortisol?

A

One of the body’s stress hormones and is secreted in times of high stress and/or famine. It plays a major role in maintaining metabolism and blood sugar balance.

64
Q

What are Androgens?

A

Specific sex hormones such as Testosterone, DHEA, and Androstenedione that helps play a role in menstrual cycle health and fertility as well as brain health, bone development, and red blood cell production

65
Q

What does the adrenal medulla do?

A

The inner portion of the adrenals, it produces catecholamines, which are the body’s fight or filght hormones Epinephrine and Norepinephrine, also known as adrenaline and noradrenaline.

66
Q

Can the adrenals store hormones like the Thyroid?

A

No, it produces them on an as-needed basis which means the adrenals usually have a ton of work to keep up, which is why many people have issues with their adrenal health.

67
Q

What are the Gonads - Ovaries?

A

Ovaries are responsible for producing the majority of the steroid sex hormones Estrogen, Progesterone, and Testosternoe throughout a female’s fertile years.

68
Q

When do the gonads produce these hormones?

A

In response to the pituitary hormones LH and FSH.

69
Q

What do the gonads do?

A

They facilitate ovulation, reproduction, and the menstrual cycle

They regulate mood, increase insulin sensitivity, help to support healthy blood sugar balance, help to support bone health by improving bone mineral density, as well as sleep regulation and heart health

70
Q

What are peptide hormones?

A

Hormones that are made up of amino acid chains
Roughly 3-20 amino acids long

71
Q

What are polypeptide hormones?

A

Also known as protein hormones, they are usually 25+ amino acids long. They are water-soluble hormones, meaning they can freely travel through the blood without a carrier and can be eliminated easily through the urine.

72
Q

What are examples of peptide and polypeptide hormones?

A
  • Anti-diuretic hormone
  • Oxytocin
  • Prolactin
  • Parathyroid hormone
  • Human growth hormone
  • Insulin
  • Glucagon
73
Q

What are steroid hormones always derived from?

A

Cholesterol; for this reason they are lipid-soluble and hydrophic in nature. In order to travel through the bloodstream, they need a carrier protein such as as sex-hormone-binding globulin, corticosteroid-binding globulin, and albumin.

74
Q

What are examples of steroid hormones?

A
  • Aldosterone
  • Estrogen
  • Progesterone
  • Testosterone
  • DHEA
  • androstenedione
75
Q

What are amine hormones?

A

Similar to amino acid hormones, as they are derived from the amino acids Tryptophan or Tyrosine.

Depending on the hormone they may either be water or lipid-soluble in nature.

76
Q

What is commonly referred to as the mother hormone?

A

Pregnenolone

77
Q

How does steroid hormone synthesis work?

A

This is how steroid hormones are produced and this process takes place within the adrenals, ovaries, and adipose tissues.

78
Q

What are the main estrogen hormones?

A
  • Estrone (E1)
  • Estradiol (E2)
  • Estriol (E3)
79
Q

What is Estradiol?

A

The most potent of the estrogens and is the most abundant in a woman’s reproductive years. It is produced from the conversion of Testosterone.

80
Q

What is Estrone?

A

Quite abundant and potent and the dominant form of estrogen after menopause, contributing to the most estradiol production at that time.

Commonly produced from androstenedione within the adipose tissue.

81
Q

What is Estriol?

A

Weakest of the estrogens and is typically higest only during pregnancy, being produced from the placenta of pregnant women. it can also be up-regulated when inflammation, specifically gut inflammation is present.

82
Q
A